The present invention relates to powder-actuated tools and, more particularly, to an improvement or attachment permitting the successful driving of relatively small-diameter washered and nonwashered fasteners from an indirect-acting tool.
Indirect-acting, powder-actuated tools adapted for driving fasteners into hard receiving materials, such as metal, masonry, concrete and the like, are well known in the art. One such tool is disclosed in U.S. Pat. No. 3,066,302. Tools of this type, while effective, suffer from a lack of versatility in that use with small-diameter fasteners, i.e. fasteners having a shank diameter appreciably smaller than the diameter of the barrel bore of the tool, requires the attachment of one or more bore-sized washers to the fastener for centering and guidance thereof during driving. Use of such washers is sometimes undesirable, however, as they may be retained on the fastener after driving, rendering impossible the flush-mounting of an item against the surface to which it is attached. Further, the use of such washers leaves the bulk of the fastener shank unsupported during the driving process. Such small, unsupported fastener shanks are subject to bending or buckling during insertion into hard receiving materials, whereby reliable installation of such fasteners may be difficult to achieve.
It is, therefore, a primary object of the present invention to provide means whereby relatively small-diameter fasteners may be reliably driven by existing indirect-acting powder-actuated tools.
It is a further object to provide means whereby such fasteners may be driven by such tools without the addition of washers or other such guiding members and with minimal recoil.
The above and other objects as may hereinafter appear are achieved by an adapter, carried on the muzzle end of the tool barrel and having a bore wherein is operatively disposed an adapter piston adapted for co-operation with the tool piston, the adapter being provided with means for retaining a fastener therein prior to driving thereof. More specifically, the adapter bore comprises two portions: a first portion, of a size to slidingly admit the shank of the tool piston, and a second portion, having a diameter of a size to guide and support the fastener during driving thereof. The adapter piston includes a head slidingly fitted in the first portion of the adapter bore and a shank so fitted in the second bore portion. The adapter piston is preferably spaced apart from to tool piston when both are in the driving or ready-to-fire position, whereby tool recoil is reduced.